The objectives of the research project center around the description of how humans perceive, remember, and utilize auditory information. The research is carried out within the framwork of an auditory information processing model. An information processing model accounts for the memory structures and psychological prcessess intervening between stimulus and response. The proposed work is carried out in two research areas. The first area is concerned with the dynamics of auditory perception in the recognition-masking paradigm. In this task, it is possible to evaluate the influence of one stimulus on the recognition of another when they occur at different points in time. In the recognition paradigm, the observer's task is to recognize two or more test signals. The test signals might be short tones differing in pitch, timbre, or loudness, vowels, or short syllables. The second area of study utilizes functional measurement techniques to study what acoustic features are functional in speech perception, and how the features are integrated together in the perception of a speech sound. This approach makes use of factorial designs to test various quantitative models of the speech perception process. The goals include the definition of acoustic features in speech perception, the manner in which the features are evaluated and integrated, and the formulation of a process model of the early stages of speech perception.